Collagen is the most abundant protein in humans, comprising 1/3 of the total protein and 3/4 of the dry weight of skin. Collagen abnormalities are associated with many human diseases, including arthritis. The overall objective of the proposed research is to extend the fundamental understanding of the structure and stability of the collagen triple helix that we have acquired during the previous grant period and to create collagen mimetics and conjugates of potential utility for clinical indications. Specific Aims: The three Specific Aims of this research proposal apply methods and ideas from physical organic chemistry, peptide chemistry, biophysics, microbiology, matrix biology, and dermatology. Aim 1 employs a newly appreciated force?the n-to-?* interaction?and other physicochemical interactions to generate an optimal collagen mimetic peptide (CMP) for annealing tightly but noncovalently to damaged collagen. Aim 2 uses CMP conjugates to probe the collagen displayed on the surface of a pathogenic bacterium, Streptococcus pyrogenes, and to antagonize its infectivity. Finally, Aim 3 uses CMP conjugates to assess burn wounds in human skin. Significance: The results of the research proposed herein will provide insights into the structure and stability of the collagen triple helix in natural contexts, and will use those insights to develop the basis for transformative molecular therapies for microbial infections and burns.